Rendering images based on three-dimensional geometry data produces two-dimensional images that can be displayed to a viewer. These images are rendered at a particular resolution. The discrete sampling nature of such rendering techniques can produce image artifacts such as aliasing. Various techniques may be employed to reduce the effects of aliasing. One such technique is supersample anti-aliasing. In supersample anti-aliasing, an image is rendered at a fine resolution and then down-sampled to produce the final image. The down-sampling effectively filters the image to reduce aliasing artifacts. In one example, each pixel of a final rendered image is generated using 16 samples per pixel. However, such techniques require additional processing capacity (or additional time) to generate the image at the higher resolution. In applications such as real-time image generation for video, each image must be generated within a fixed duration in order to meet frame rate demands of the display system. These requirements can limit the complexity of a scene being rendered and/or reduce image quality.
A workaround to this issue has been developed that is referred to as temporal anti-aliasing (TAA). In TAA, different samples for a pixel are generated in each successive frame and then the samples from different frames are combined to generate the final color for each pixel in the current frame. For example, one sample may be generated for each pixel in the current frame and then filtered with color values for that pixel in the previous N frames to come up with a filtered color value for the current frame. The sample location is changed each frame so that the filtered color value for the current frame may approximate a color value generated using a supersample anti-aliasing technique. This could result in a good approximation if the underlying geometry data is consistent across the N frames, but in most cases, there will be some objects that move within the scene from one frame to another, or the virtual camera position may move relative to the objects from one frame to another. When this happens, artifacts may appear due to filtering color values from different objects across a number of different frames. Ghosting of moving objects or changing specular highlights can cause significant reduction in image quality. Thus, there is a need for addressing these issues and/or other issues associated with the prior art.